is this piston damaged?

well i pulled the head on my 2.5 after bending a valve, a rocker arm, a push rod, and breaking the spring retainer on the #1 cylinder. im worried about the piston being damaged, i can see the valve looks like it hit it, how is this gonna affect my piston? is it ruined? heres a dumb question, how hard is it gonna be to have to replace it? also, can i run it like it is? here are some links to pictures.

http://xyourfuneralx.tripod.com/engine5
http://xyourfuneralx.tripod.com/engine1
http://xyourfuneralx.tripod.com/engine2
http://xyourfuneralx.tripod.com/engine3
http://xyourfuneralx.tripod.com/engine4


crap i think the pictures are huuuuuuuuuuuuuuge. and i dont know why. ill try to scal em downand post one, ill re post the others later cause i gotta run. engine 5 is the normal sized one the rest are very very large.

It'd be nice if you'd put a file type extension on them as well.

xXJx said:

crap i think the pictures are huuuuuuuuuuuuuuge. and i dont know why. ill try to scal em downand post one, ill re post the others later cause i gotta run. engine 5 is the normal sized one the rest are very very large.

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*best mr. meogi voice* focus danielson, focus

fordtech said:

*best mr. meogi voice* focus danielson, focus

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99% of your digis dont really focus.

Ghost said:

99% of your digis dont really focus.

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99% of MINE do!

ChiXJeff said:

It'd be nice if you'd put a file type extension on them as well.

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ya but then tripod wont host em. they are jpegs.

yeah i would say that piston is gone



www.imageshack.us

heres new pictures. so you guys think its toasted? what would happen if i got that valve fixed that cause this(pic 3)? how hard is it to throw a new piston in there?

these are thumbnails by the way they get bigger i think.

Drop the pan
Unbolt the rod journal
Push the piston up out of the hole
Use a ring compressor when poking the new piston back in

PearlCountry said:

Drop the pan
Unbolt the rod journal
Push the piston up out of the hole
Use a ring compressor when poking the new piston back in

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If possible rent buy borrow or steal a ridge reamer*
too, to prevent ring damage.

* Ridge reamer removes the buildup of crud and the slightly raised metal at the top of the cylinder bore. If the engine is old enough and worn enough, you may need this even to get the old piston out.

PearlCountry said:

Drop the pan
Unbolt the rod journal
Push the piston up out of the hole
Use a ring compressor when poking the new piston back in

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In a nutshell.

PearlCountry omitted a couple of points. The wristpin is a press fit into the piston, and the connecting rod is sized to turn on the wristpin. So you'll have to have the replacement piston pressed onto the connecting rod at a machine shop set up to do that work. The rods and pistons are directional, so mark which side of the rod faces forward when you remove it, be sure the shop presses the new piston on with the same orientation as the old one, and be sure to put it back in the engine with the front facing the front.

And follow Matthew's advice on the ridge reamer. If you don't cut the ridge away before removing the old piston you'll probably break either a ring or one of more of the piston lands. No great loss on the old piston, but it would be a shame to break a new ring or the new piston trying to shove it into the bore past that same ridge.

Is that piston just scuffed and/or gouged, or is there actually a crack in it? I cannot tell from the pics.

If it's just scuffed and gouged bit, maybe some shade tree mechanic buffing with a sander will get the surface cleaned up enough.

AZ Jeff said:

Is that piston just scuffed and/or gouged, or is there actually a crack in it? I cannot tell from the pics.

If it's just scuffed and gouged bit, maybe some shade tree mechanic buffing with a sander will get the surface cleaned up enough.

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the topic of shade tree mechanics has come up many times in this ordeal ive been having, the funny thing is the jeep sits under a big lemon tree for shade. .

ya those circle lookin thinks are just very light scruffs, but there are some small gouges in there towards the top right. those are what im worried about, but the $11 for a piston isnt too bad. wow im glad its not that much of a problem. i guess ill order new rods and rocker arms while im at it cause it bent one of the old ones.

a new piston, piston rings of course, and a valve job on that #1 cylinder and i think ill be back in action after letting it set for over a year.

how can i tell what size pistons i have? is there a number on the engine somewhere?

Personally, if the rod isn't broken or bent, I would probably just take a bit of sandpaper and knock off the rough edges and fix the head. I would be more worried about the corresponding lifter, pushrod, rocker, and cam lobe. I would also inspect the casting around the rocker studs. I have seen studs start to pull out. If you pull the piston to check it, you will probably have problems with the rings not seating if you put it back in. If you replace the piston, use a cast iron ring, use a good ring land reamer, and hone the cylinder well. If you don't get the ring land down even with the ring wear pattern, you run a big risk of breaking the new rings the first time you start it up.

A tip for removing the varnish on the piston. Castrol SuperClean disolves the varnish in the ring lands and on the back of the piston like magic.

old_man said:

I would be more worried about the corresponding lifter, pushrod, rocker, and cam lobe.

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well the rod is bent, rocker is bent too, already got those, havent checked the lifter or the cam lobe though, looks like problems arnt all taken care of after all.

xXJx said:

well the rod is bent, rocker is bent too, already got those, havent checked the lifter or the cam lobe though, looks like problems arnt all taken care of after all.

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Since you already have the motor torn apart maybe you should just go for a total build over. Maybe you can score a deal on a sealed power rebuild kit or somthing with all the necessary parts and have the machine shop stuff done. I don't know what your budget is though.

ok, now Ill try to be helpful...

If that is indeed only a light indentation, and there is no sign of hard contact, I would clean it up and run it. Just scuff up the surface and clean it up, take off any high spot that the indent might have caused (if it was truely light contact, there really shouldnt be a ridge).

If you feel like you should replace that piston, then get a rebuild kit too(they even make one for the 2.5??). This should include all gaskets, bearings, rings, timing chain, so on.

I would also go for the full rebuild. I wouldn't take the chance that one part in the engine is faulty to mess up an entire engine and cost more in the long run. Or find a used engine to run while you rebuild the original engine. I just got done putting in a used engine that cost me $350.00. It runs great and now I have an engine to do a rebuild on and possibly put a few mods in the engine to get some more power out of it. The 2.5 is a good engine and worth a good rebuild.


Kim.

It might depend on how much you enjoy the challenge of shade tree mechanics and the adventure involved in seeing how little you can get away with. I don't mean that as a slam - doing something like this on the cheap can be fun and very rewarding as long as you remember it's a bit of a gamble. Since you're not paying for labor, you can often do well by being cheap but very careful. But if the valve hit the piston hard enough to bend a rod, I think a new piston is probably a good idea, and if you're replacing a rod and fixing the head, I think at least a new set of rod bearings would be a very good idea. Often when an old engine gets a fresh head, the next thing to go is the rod bearings. Assuming the crankshaft is good, a new set of bearings could be cheap insurance.

Another option if you really like doing this sort of stuff and have time to do your own work is to get a price on a rebuild from a shop, and a price on a rebuilt long block engine. Now with that in mind, price all the parts you would need to do the rebuild properly yourself, and the special tools you'd need. You'd need at least a ring compressor, valve compressor, ridge reamer, cylinder hone, and a few other odds and ends. There's a chance you could do it yourself cheaper or for about the same price, and you get to keep a bunch of very neat tools.

Matthew Currie said:

It might depend on how much you enjoy the challenge of shade tree mechanics and the adventure involved in seeing how little you can get away with. I don't mean that as a slam - doing something like this on the cheap can be fun and very rewarding as long as you remember it's a bit of a gamble.
You'd need at least a ring compressor, valve compressor, ridge reamer, cylinder hone, and a few other odds and ends. There's a chance you could do it yourself cheaper or for about the same price, and you get to keep a bunch of very neat tools.

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well im blessed to have an entire 12x6 snap on tool box filled with snap on, mac, and matco tools. ive got pretty much every tool in there anyone could possible ever need. my step dad and mom got divorsed and i jacked all his tools
he also worked for renick cadilliac in fullerton, and he took my jeep down there and had the whole thing gone through, whole top end rebuild was done. that was in the past 15k on the jeep.
i love working on cars, i do it alot. i just havent gotten into engine rebuilding until now. well i figure ill get the head taken care of today, bolt it back on and run it. if it dont work right, il go get that cylinder and switch out those rod bearings like you said, and if that dont work, pick a part is having a half off sale this weekend and i could score an entire engine for $85.